Jet engines employ air valves for a variety of reasons including, but not limited to, passenger compartment cooling, turbine clearance, and compressor bleed. Generally, these air valves require some type of rotary actuation. Different types of actuator mechanizations have been developed for these applications including, but not limited to, rotary vane actuators (RVA), linear crank sliders, Scotch yoke actuators, reverse Scotch yoke actuators, rotary piston actuators (RPA), and rack and pinion actuators.
The most common mechanism for converting linear force into rotational torque in air valves used on aircraft turbine engines is the linear crank slider. The linear crank slider has several disadvantages, chief among them: 1) Large overhanging mass due to length needed to implement the mechanization which adds to the size, weight, and cost of the system; 2) Linear seal and scraper at fluid/air boundary in harsh environment which adversely affect reliability; and 3) Linkage and associated bearings exposed to harsh environment which adversely affect reliability.
It would therefore be desirable to have an air valve actuation system that addresses the shortcoming recited above. Embodiments of the present invention provide such an air valve actuation system. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.